I haven't checked all my accounts, but it's happening at least in Stack Overflow, Meta and Board and Card Games. This morning, I could see my other accounts just fine. It's a bit of a bother because I use those links to change between my accounts.

I don't get it, every time this happens someone files a bug. It says "Profile information is temporarily unavailable" -- which part of that screams "unexpected bug"?
–
Michael MrozekJun 17 '12 at 1:28

2

@Michael, I am to blame for that part about seeing that message. When I edited, there were no hits for "0 Accounts", so I added that. And I could not post an answer about clicking the header (not too obvious, I'd say) as this question was still closed at the time. I've moved that part into the answer now. Hope this will stay around for future reference...
–
ArjanJun 17 '12 at 6:20